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By G. Le Bel

The paper proposes three methods to determine optimum lifetime of a mining project1. The conclusion is that the three methods arrive at the same optimum production rate (by coincidence). It is also stated that: "The stochastic and option pricing models, in addition to providing a more realistic optimum mine life than the traditional NPV (net present value) calculation, showed that the example project has the potential for substantially higher return. By explicitly considering a project's potential risks, the stochastic or option pricing techniques can more accurately describe its probable investment performance." This discussion is intended to demonstrate that: • It is no coincidence that the three methods arrive at the same optimum production rate. • The stochastic and option pricing models do not provide a more realistic optimum mine life than the traditional NPV calculation. • The potential for a substantially higher return is misrepresented. First, a review of investment decision theory in mining is needed. Net present value is the preferred performance measure because of the flexibility offered when comparing various alternatives. However, it presents the following disadvantages: • The discount rate selection is not straightforward. • The NPV obtained represents a deterministic characterization of the variables included in the cash flow calculations, i.e. a single-point estimate.

Jan 1, 1993

By Howard J. Handewith

Long used in mine development in England, Europe and Russia, roadheaders are growing in size, features, productivity and application. Beginning with the basics, this paper covers the economic and the technical aspects of the new roadheaders in both mine production and development. The author explains how to choose and integrate roadheaders into ongoing operations as another step in the inexorable march from labor to capital intensive mining. Innovations now on the drawing boards are covered that are the challenge of the future.

Jan 1, 1983

By J. M. Wempen

Booster fans in underground coal mines are often located using the concept of a neutral point. Normally, intake airways are maintained at higher absolute pressure than return airways, so air leaks from intake to return. By adding a significant pressure force to a region of a ventilation system, booster fans installed in a return airway can increase the pressure in the return so that air leaks from return to intake. This is commonly referred to as recirculation. The neutral point occurs at the location in the system where the pressure difference between the intake and the return airway(s) is zero and at this point there is no leakage or recirculation. Ideally, placing a booster fan near the neutral point minimizes leakage and recirculation; however, in practice the position of the neutral point is not static and it changes as the ventilation system parameters change. This paper presents a study of how changes in the system parameters affect the location of the neutral point in a model coal mine ventilation system. First the effects of booster fan pressure and location on the neutral point are evaluated. Next the effect of increasing mine distance, and therefore mine resistance, on the location of the neutral point and the magnitude of recirculation is evaluated.

Jan 1, 2012

By S. Agarwal

The mining industry collects a significant amount of operational data. However, gleaning useful information from the terabytes of data is difficult, and not just because of the sheer volume of the data. Therefore, an automated tool was developed at the University of Alaska Fairbanks to go through data and apply very sophisticated statistical and neural network techniques, to identify the data streams that are important to a process. This paper presents results from the tool as applied to SAG mill data from a gold mine. The results were benched against commercial tool. Results indicate that there was little or no loss in performance by automating the very complicated process of neural network modeling. Therefore, the intent of the exercise, to examine if complicated modeling tasks can be automated, was realized.

Jan 1, 2011

By P. S. Baker

CRU estimates that the global supply of metallurgical grade alumina (MGA) grew by 5 percent during 2005 to a little more than 61 Mt (67 million st). About 30.7 Mt (33.8 million st), or 50.3 percent, of that originated from Oceania (principally due to the commissioning of the CAR refinery in Australia) and Latin America. In this context, Chinese production surged by 20.5 percent year-on-year to 7.7 Mt (8.5 million st) on the crest of a 17-percent rise in that country’s primary aluminium production. Meanwhile, on the demand side, there was a 6.7 percent climb year-on-year in global consumption to 62.3 Mt (68.6 million st). This reflected a healthy demand for primary metal from aerospace, construction, packaging and passenger transportation (to a lesser degree) in the United States, China, Brazil, South Korea and India. So there was an overall supply deficit of more than 1.2 Mt (1.3 million st). This, combined with an 18.3-percent diminution in closing stocks (down to 35 days of requirement), lifted the average spot price of MGA by 17.6 percent year-on-year to US$448/t (US$406/st).

Jan 1, 2006

By J. M. Barker, V. T. McLemore

Most discussions of sustainable development (SD) in mining relate to metal mines in rural areas. Industrial minerals (IM) are closer to urban areas primarily owing to a high transport-cost component of delivered cost. This visibility to large populations overshadows IMs relatively small operation size and generally lower waste volume and toxicity. The IM industry needs to rethink its way of doing business to fit into the SD paradigm. Society and business in general will also undergo significant change to enable industrial SD along the lines of triple-bottom-line accounting with government pushing everyone. The benefit to IM mining from embracing SD is a renewal in their social license to operate and a rebirth of mining as a positively-viewed force in society. This positive view would lead to lower acquisition costs because society would not fight so hard to eliminate nearby mining. This would ease the current exploration woes of the IM industry by opening up new deposits for exploration and more readily allowing placement of mines nearer to markets. The earlier in the exploration process SD is initiated, the better.

Jan 1, 2004

The National Mining Association’s (NMA)MINExpo International ’96 is shaping up to be the organization’s largest. About 30,000 mining industry business and technical professionals are expected to descend on Las Vegas, NV Sept. 9-12 to take part in the 25 technical sessions and visit the more than 900 exhibitors who will be showing off their products and services. MINExpo will be the largest mining equipment and services exposition in the United States this year. Exhibits at MINExpo will fill the Las Vegas Convention Center, parking lots and part of the Hilton Center, located next door to the convention center. NMA estimates that this year’s show will cover more than 46,450m2 (500,000 sq ft) of exhibit space. Some of the exhibits on display will include haultrucks, hydraulic shovels and excavators, conveyors, continuous miners and tunneling machines. In addition, an array of computer equipment and software will be demonstrated. A new feature this year will be a helicopter pavilion, located in the Hilton Center. Helicopters and fixed-wing aircraft have become indispensable to many remote mining operations. NMA said that at least one full-size helicopter will be on display.

Jan 1, 1996

By R. W. Smith, D. L. Taylor, K. A. Altman

Recent research has shown that traditional sensitivity, what if and best case/worst case analysis of metallurgical data has the potential to over estimate the value of mining projects. Use of simulations, which rely on the input of statistical information, may provide more realistic predictions of the value of future projects. Actual metallurgical data is used to demonstrate that analyzing the data from a statistical perspective can give insight into completing an optimum amount of metallurgical testing and a mechanism to determine that samples used for the testing are truly representative of the ore that will be processed.

Jan 1, 2000

By C. C. Russelll, V. T. McLemore

The Metals Mining Sector of the Acid Drainage Technology Initiative (ADTI-MMS) addresses technical drainage-quality issues related to metal mining and related metallurgical operations, for future and active mines, as well as, for historical mines and mining districts. One of the first projects of ADTI-MMS is to develop a handbook describing the best sampling, monitoring, predicting, mitigating, and modeling of drainage from metal mines, pit lakes and related metallurgical facilities based upon current scientific and engineering practices. One of the important aspects of planning a new mine in today’s regulatory environment is the philosophy of designing a new or existing mine or expansion of operations for ultimate closure. The holistic philosophy taken in the ADTI-MMS handbook maintains that sampling and monitoring programs should be designed to take into account all aspects of the mine-life cycle. Data required for the closure of the operation are obtained throughout the mine-life cycle, from exploration through post-closure.

Jan 1, 2004

By L. Gertsch, R. Gertsch

Mechanical mining is steadily gaining usage in the mining industry. A variety of machines currently finds employment: tunnel boring machines, roadheaders, continuous miners, surface miners, and augers. These machines have advantages compared to drill and blast mining methods, including increased safety, lower cost, uniform muck size, and accurately sized openings. A century of experience with mechanical methods has already paid dividends to the coal industry. Current trends guarantee eventual development of true general-purpose hardrock mechanical mining machines. Mechanical miners will become integrated mining systems and will determine the design of mines, when several significant challenges have been met.

Jan 1, 2001

By A. E. Koski

Two of the largest industries in northern Michigan, pulp and paper manufacturing and iron mining, formed a mutually beneficial partnership and collaborative research program to utilize paper mill residuals for waste rock stockpile reclamation. Historically, the majority of the paper industry’s residuals have been disposed of in landfills. The beneficial use of paper mill residuals for mine reclamation provides an environmentally sound recycling solution for the solids generated at northern Michigan paper mills and eliminates the need to strip additional overburden (glacial till) for final mine reclamation. Residuals offer a cost-effective source of organics and nutrients necessary for successful reclamation and waste rock stockpiles offer an economical and environmentally sound solution for disposal of residuals. The goal is to successfully pioneer technical development of paper mill residuals to accomplish vegetation of steep waste rock stockpile slopes and benches to establish a self-sustaining plant community that meets final reclamation requirements. Of the various types of iron mining wastes, rock stockpiles pose the greatest reclamation challenge. Success depends on incorporating sufficient organic matter into the rock stockpiles to produce a growth medium that can sustain vegetation without the need of overburden. This is an ongoing research program that is evolutionary in nature with numerous field trials, greenhouse studies, data collection and monitoring over multiple growing seasons. The program is a combination of innovative ideas and accepted reclamation practices that is proving to be a beneficial and economic approach to paper mill residual management and mine reclamation that will eventually lead from research to standardized reclamation procedures.

Jan 1, 2006

By Herbert H. Einstein

Swelling ground is one of the most feared problem in tunneling. Although usually not causing sudden failures during construction, the very large and long- lasting deformations give contractors and designers the impression of facing an inevitable phenomenon against which there is no technical defense. Examples are concrete liners of up to 1 m that have been cracked or crushed, tunnel inverts that are heaving at a rate of 0.1 m per week during construction and continue to heave during decades. This author (Einstein (1979). Einstein et al. (1972) (1975)) and others (Huller (19761, Grob (1972) (1976). Golta (1967), tienke (19761, Krause (1976). Lee et al. (1976)) have described many cases of swelling tunnels that illustrate the significance and magnitude of the problem. This paper intends to show that tunnels in swelling rock can be built to perform satisfactorily. . For this purpose the tunnel builder needs to know how to determine the existence and specific behavior of swelling ground, how to select appropriate structural characteristics of the tunnel and predict its performance under the specific ground conditions, and finally how to construct the tunnel such that the anticipated performance will be achieved. This concept of a design-construction procedure is the same as that for tunneling in general; it is mentioned here for NO reasons: 1. To point out that design and construction cannot and should not be separated. The way in which the tunnel will be built has to be an integral part of the design. 2. This paper will be structured corresponding to the procedural concept.

Jan 1, 1981

By C. H. Bucknam

Principles of Green Chemistry provide useful guidance for sustainable mineral process development. Laboratory bench scale testing was carried out using pregnant cyanide leach solutions, and a number of commercially available mercury precipitation reagents were compared using jar testing to determine the most efficient and selective reagents for mercury precipitation. The most efficient reagent identified was sodium polymeric thiocarbonate (NaPTC).Coagulation experiments with fine diatomaceous earth resulted in a stable precipitate, with good settling properties. On line monitoring of the mercury in solution is recommended for process implementation to conserve reagent removing approximately 90-95% of the mercury with minimal silver and negligible gold losses.

Jan 1, 2004

By Lawrence H. Roth

Past failures of coal refuse embankments have resulted in intensified efforts in inspections of coal refuse sites by the Mining. Enforcement, and Safety Administration (MESA). MESA inspections however, are mainly qualitative and are often time consuming, Therefore, in August 1975 CH2M HILL was awarded a contract to identify, develop, and test a rapid system for monitoring coal refuse embankments to aid in MESA inspections. The rapid monitoring system developed uses convergent and vertical photography from conventional fixed-wing aircraft. The system was tested on an active landslide and on two coal refuse facilities using both black and white and color infrared film. Field tests showed the system was capable of accurate measurement while providing qualitative data through photo interpretation. The accuracy of the system allows it to be used to monitor coal refuse embankments, tailings dams, major earth dams, and natural slopes. Based on CH2M HILL results cost for monitoring by rapid system was approximately 25 percent of cost by conventional ground survey.

Jan 1, 1980

By Marion Loomis

Environmental regulation is an ever growing cost to the mining industry. Requirements for such items as air quality modeling, hazardous waste disposal, selenium concentration in water and sagebrush planting consume more of the mining industry’s resources each year. The mining industry is willing to make the necessary financial commitments to assure that the air, land and water resources are adequately protected and restored. However, it is sometimes difficult to explain to management and stockholders why money should be spent on a specific issue when science and common sense indicate it is being wasted. Common sense and sound science should dictate how mining is regulated.

Jan 1, 1994

By M. Deal

Particle size analysis is a fundamental measurement utilized in the mining industry, especially in comminution, hydrometallurgy, and mineral processing. While sieves and cyclosizers are the standard methods used to determine particle size distributions, in recent years alternative instruments have been developed that claim to provide more rapid and equally reliable results. Newmont Metallurgical Services has implemented the use of two such instruments, along with traditional methods (sieves and a cyclosizer), on a daily basis. The Malvern Mastersizer 2000 laser analyzer is a wet sample system that can analyze particles in the size range 0.02µm to 2000µm, and the Horiba CAMSIZER® is a dry system that can analyze particles in the size range of 30µm to 30mm using digital image processing. A comparative analysis has been performed to determine the applicability of each particle sizing method in laboratory testing.

Jan 1, 2011

By D. R. Hack

Increased consumption of concrete in the Pacific Northwest has pushed aggregate resource development pressure from urban areas west of the Cascade Range to rural areas east of the Cascades. Some recent development has focused on barge and rail accessible off-reservation Indian allotments that are exempt from state and county regulations. These lands have their own unique set of challenges, especially when Federal and Tribal governments have conflicting goals and attitudes pertaining to resource development. This paper discusses issues of leasing, reclamation, Federal vs. Tribal authority, cultural resources, and the history of allotment.

Jan 1, 2002

By P. Mills

More than 95 percent of all the barite mined and produced is used in the petroleum industry as “drillers mud.” The remaining barite is used in the industrial and medical markets. Therefore, the amount of drilling activity is a good indicator of the health and growth of the barite industry. The four major barite-producing countries in the world are China, the United States, India and Morocco. In 2005, the average number of drilling rigs exploring for oil and gas increased by about 15 percent over the average number in 2004. This increase in oil and gas exploration has resulted in a higher demand for barite and an increase in barite production.

Jan 1, 2006

Cement in 1975 indeed did operate in an unfriendly environment. World recession, escalating costs, fuel crises, reduced product demand . . . . all led to market conditions detrimental to industry profit margins and investment re turns. During the year plant utilizations fell, break-even points were raised, and competitive moves introduced to move built up inventory levels. A number of cement plants were temporarily taken out of production to help alleviate specific situations. Meanwhile, under resultant financial pressure, several companies omitted dividend payments, changed their top executives, and reorganized and reduced staff overheads. It was a difficult year for cement, yet a much more ominous note was sounded in permanent plant closings. Four more cement operations were shut down in 1975; to date in 1976 we know for sure of three additional plant closings, while rumour has it that at least one more may not be in production by year-end. The somber feature is found within the descriptions of the closed facilities, and in the stated reasons for their being taken out of cement manufacture.

Jan 1, 1976

By M. C. Roberts

Currently, mineral producers are suffering through a major downturn in prices for their products, even though it has only been a few years since they were enjoying high prices. From an historical perspective, the current situation is another of the cyclical down-turns that often reoccur every 5 to 7 years or so. This paper uses time trend decomposition techniques to identify the cycles and statistical methods to find the duration of these cycles for a variety of mineral prices. Given some idea of how long and severe these cycles typically are, the mining industry can better plan to weather the downturns and take advantage of the upturns. For example, timing investments in new projects to take advantage of the cyclical upturns can dramatically improve project profitability.

Jan 1, 2000